With over 350 releases to its name, Ernesto Rodrigues' Creative Sources label shows no signs of slowing down. And while it's true that a list as long as this will inevitably contain a few clams, this is not the case with the disc at hand. The Iridium String Quartet consists of Maria Da Rocha (violin), Ernesto Rodrigues (viola), Guilherme Rodrigues (cello) and Miguel Mira (double bass), offering up two long pieces of string tangle and chordal float, assembled with patience and attention to detail.

The first piece builds from a sibilant hiss into harmonic-laced clouds pocked with occasional plucks and clunks, rising and falling again to build anew. At around the 13-minute mark a denser collection of squeak eventually dissolves into a rich shifting drone. During the busier sections, alien timbres arise, sounding more like ghostly wind instruments than bowed strings. I swear I can hear a flute at one point. It's 26 minute play time seems to zip by in an instant.

The second, longer piece seems to carry on logically from where the first ends. Indeed only a quick check of the CD player's counter confirms that things have begun over. Here the quartet spreads out a bit, with two duos at times sparring with each other, feedback-like whines hanging over low-end tussle. The rise and fall familiar to many listeners of improvisation would seem to be the modus here. Ideas are offered, added to and expanded for short periods before easing away to near silence, like a string of beads or a list of favorite notions. Like most Creative Sources discs, the recording here is gorgeous, allowing close inspection of the grain and whistle.